User blog comment:MegaGyarados/PokéPolls - Episode 2 - Nominations - Hardest Gym Leader/@comment-32358261-20180210232136/@comment-32358261-20180210232706

Second hardest was probably the ground gym. That mega garchomp deals so much damage. My team was better established and I had my own garchomp to counter it

Third was flying gym. That level curve was awful. From lv 30 Wild pokemon to lv 50 gym leader pokemon. Greninja was level 42 and could handle a few weaker Pokémon and my lv 40 ampharos was too slow. I would have taken eevee and evolved to jolteon but I had to all the way back to the first city and go back then train it. The gym itself wasn’t hard. The high level Pokémon was the issue